GRAIN ELEVATOR, a structure equipped with adjustable elevating machinery for the purpose of unloading and storing grain, which is subsequently loaded directly into rail way cars, canal boats or grain-carrying vessels for transportation. In addition to these primary services the modern grain elevator has machines for cleaning the grain, drying it if necessary and weighing it.
• The smaller or °country* elevator consists generally of a building or *house* surmounted by a smaller structure called the The house is divided into a series of deep storage bins, while the cupola contains the machinery for operating the °elevator leg,* the turnhead spouts, the garners, the weighing machines and the cleaning machinery. It is usually con structed of timber with brick outside walls for the house, and corrugated sheet iron for the roof and walls of the cupola. Many elevators, practically firepoof, are built with solid brick walls enclosing steel bins surmounted by steel framed cupolas roofed with terra-cotta or sheet iron, while in others the construction is of structural steel encased with concrete. Fur ther protection is obtained by housing the .steel storage bins and the operating machinery in separate fireproof buildings, the grain being handled between them by a system of pneu matic conveyers. Since 1902-05, a period of ex perimentation with not a few failures, the pre ferred material for grain elevator construction has been reinforced concrete, even for the smaller buildings. The first cost is usually 20 per cent higher than for wood, but the very large saving in insurance and depreciation soon account for that difference. The larger plants are now built with a °working house" and a storage section adjacent. In the working house is gathered all the machinery, and it often con tains considerable storage room. The concrete bins are cylindrical and built touching each other, and the spaces between them are also used as storage bins. The largest grain elevator of this type in the world has recently been com pleted for the Armour Grain Company, on the Calumet River at Chicago, at a cost of $3,500, 000. The working house has 93 bins 14 feet in diameter and 74 feet high, with a capacity of 931,000 bushels. The main storage bins are 130 in number, 22 feet in diameter and 104 feet high, with a combined capacity of 4,383,000 bushels. The working house has six receiving legs, six shipping legs, eight cleaner legs, five clipper legs, three screening legs, six drier legs and three bleaching legs. Each leg has a capacity of 10,000 bushels per hour. The walls
of the storage bins are uniformly 7 inches thick. Some of the great Canadian elevators have bins over 30 feet in diameter and 8 inches thick.
There are two distinct types of grain ele vating machinery: that in which the grain is carried up by buckets attached to an endless belt traveling in the "leg? and the pneumatic elevator, in which the grain is sucked up a tube by a current of air. In the first type the leg is a two-chambered construction, the endless belt carrying the buckets running up one chamber and down the other, the whole being capable of vertical adjustment —hoisted high so as to pass over the side of a great ship, or lowered so as to touch the bottom 40 feet or more below. In operation the leg is lowered into the cargo of grain and swiftly running belt scoops up the grain in its buckets and empties it in a re ceiving chamber. Here it is taken by another belt called the lofting belt and carried to the top of the elevator to a hopper known as the garner. Immediately below the garner is the weighing apparatus into which the grain falls through a spout, and from which it is sent on ward to the cleaners if necessary and then to the storage bins. In the pneumatic system there is no leg, but the suction tube hangs from the end of a hollow crane-like boom which can be swung over the vessel to be unloaded. This tube is flexible and telescopic, so that it can be made to reach any level and into the farthest corner of the vessel's hold. A powerful vacuum pump at the inner end of the boom exhausts the air in the tube, and the air in the hold of the ship rushes up to fill the vacuum, taking the grain along with it to the vacuum chamber. From here it is directed to the scales, cleaners and bins. There are several advantages in the pneumatic system not possessed by the other. The suction tubes are flexible and extensible, and may be moved to any point in a ship where the grain may be: the elevator leg is rigid and the grain must be brought to its foot by hand labor or by supplemental machinery. In the matter of the health and comfort of the laborer also the pneumatic system leads, as it produces neither the dust nor the heat of the bucket elevator. On the other hand, the opera tion of the pneumatic elevator is considerably more expensive and this has militated against its installation in many of the newer and larger elevators. The pneumatic system has been very successfully used to transfer grain long dis tances and in this it has no competitor.